Are you joking?

1. Define "porn"

2. Get every other TLD operator, including all the international ones, on board with your definition and rules (e.g. are we only banning websites on port 80, or would FTP sites also be verboten? password-protected sites? is classical art exempt?)

3. Enforce the censorship via some kind of magical system that is automated, doesn't trigger false positives, and allows for an appeal process

Yeah, that'll be a snap to put together.

You're setting the bar too high.

Legislators will simply say that all sites that feature nudity in a non medical setting will have to be on the xxx domain name. This isn't merely just porn so it can be passed off as 'neutral' and not legislating morality but rather legislating categorizations ("bringing order to the Wild West of the internet").

Now as for how they force sites onto the .xxx domain name, the choices are:

1. Legislators then simply blacklist all sites that feature nudity in other TLDs. This could be called the "Australian" approach or the "Great Firewall of Foo".

2. Fine companies within your country that are running sites outside of the XXX TLD. If only the US and EU do this, it'll drive 98% of the money-making porn industry into the XXX TLD. Then maybe for completionism you can implement #1 against 'foreign porn peddlers'.

False positives are not a concern for legislators. If there's a worry about blowback, they'll simply make the blacklist confidential, and the appeals process non-transparent.

I can think of lots of porn that doesn't require nudity.

I can think of lots of nudity that doesn't require porn, or a medical context.

I think this is the start of a beautiful collaboration, you two.

Don't forget:

0. Repeal the First Amendment.

There are other countries...

No no, the United States constitution is a worldwide law. We invented freedom, and we invented English!

Does this First Amendment require that you allow people to release porn movies as U rated? So why does labelling online, via a dedicated TLD suddenly mean that the First Amendment needs to be repealed?

Moreover most, if not all, such "speech" (dissemination of pornography) will ultimately be commercial and so not come under the full auspice of the First Amendment protections.

Setting aside the fact that you're trolling...

The correct way to do something like this would be to use a whitelist TLD, e.g., .kids. Such would avoid questions of censorship, and of which content requires being legally shoved into the .xxx ghetto, and makes it real clear that if you put porn on a .kids domain you're going to get hammered.

My comment above links to the ghost-town that is *.KIDS.US, which - with Congressional support - tried to do exactly that. It failed then, and would fail now.

http://www.kids.us

Or in other words:

Ah yes, .xxx -- a solution to a problem that absolutely nobody had other than wannabe-censors.